A defibrillator is a life-saving device used to treat a sudden cardiac arrest (SCA), a condition that occurs when the heart unexpectedly stops pumping. The defibrillator analyses the heart rhythm and recognises abnormalities. The machine will decide whether a shock is required to be delivered to the casualty or not.
A defibrillator is commonly known as a an AED (automated external defibrillator) or a ‘defib.’.

What is defibrillation?

Defibrillation is the process of attempting to restore the heart’s normal rhythm and is crucial in the first minutes following a sudden cardiac arrest (SCA) to maximise the casualty’s chance of survival.

What is Sudden Cardiac Arrest (SCA)?

A sudden cardiac arrest (SCA) is a condition that occurs when the heart unexpectedly stops pumping.

Each year, sudden cardiac arrest strikes approximately 30,000 Australians. Unfortunately, fewer than 5% survive, often because help cannot reach them in time. Average ambulance response times is between 9 -14 minutes.

SCA is not gender or age specific.

What are the benefits of using an AED during a sudden cardiac arrest (SCA)?

For every minute that passes, the chance of survival is reduced by 10%.

Application of an AED increases the survival rate

When is a defibrillator used?

Following the DRSABCD Action Plan, if a casualty is not breathing, CPR should be commenced. A defibrillator should be applied whenever CPR is performed.
If the casualty is breathing, regardless of whether they are responsive (conscious) or not responsive (unconscious), a defibrillator is not required.

How does a defibrillator work?

A defibrillator delivers a set amount of electrical shock to the heart after it analyzes the heart rhythm. It determines whether a shock is required to the heart via adhesive electrode pads attached to the casualty’s chest. The shock delivered by a defibrillator interrupts the chaotic rhythm of the heart and gives the heart the chance to return to its normal rhythm.

Who can use a defibrillator?

Anyone can use a defibrillator – it is just a matter of following the instructions provided by the unit. However, training is recommended to give the user greater confidence.

What if I attached the AED to a conscious casualty? Can I harm them?

If there is normal electrical activity in the heart e.g. the heart is beating regularly, an AED will not allow a shock to be delivered.
For example if a person thinks the casualty is not breathing but the heart is beating, an AED will assess whether there is a heart rhythm and advise that a shock is not required. The AED will not allow a shock to be delivered.

Do I have to be a healthcare worker to use an AED?

No. An AED guides the user step-by-step through the defibrillation process with visual and voice prompts. The AED will not deliver a shock unless it detects a shockable rhythm e.g. the heart is not beating regularly.

Can a heart stop beating after an AED has got it beating again? How would I know?

Once a shock is delivered, an AED will continue to monitor the casualty’s heart rhythm. If the analysis reveals that the heart has stopped beating, it will advise that a shock is required. Follow the prompts given by the AED.

Can I shock a casualty accidentally?

No. The AED assesses the status of a person’s heart and will not shock a normal heart beat.

Why don’t I wait until an ambulance arrives?

Defibrillation is most effective when carried out as quickly as possible in the first few minutes after sudden cardiac arrest (SCA).

Do I need training to use an AED?

St John Ambulance recommends that you attend training as it will give you greater confidence in the use of a defibrillator.

Where can I get AED training?

St John Ambulance Australia is a national self-funding not-for-profit organisation, active in every State and Territory. As Australia’s largest first aid Registered Training Organisation, St John provides practical life-saving skills to more than 500,000 people each year.
St John Ambulance Australia offers a Cardiac Pulmonary Resuscitation (CPR) and Automated External Defibrillator (AED) hands-on course to train participants in this life-saving skill.

What maintenance does the AED require?

Self maintenance and visual inspection

All AEDs perform self-maintenance checks on a daily, weekly and monthly basis to ensure that they are ready for use. In the event that the machine fails part of the test, the machine will beep to alert you that there is a fault with the machine.

St John recommends a weekly inspection be performed on the machine to ensure the machine has not failed a self-check; this inspection only takes a minute to complete.

In standby mode, maintenance is simply a visual inspection.

Replacement of consumables:

Pads - every 2 years

Battery - every 4 years.

Note: The HeartStart* defibrillator units have an 8 year warranty (excludes pads and battery).

What is the St John iPhone app – Resuscitate?

The iPhone app Resuscitate makes it easier to find publicly accessible defibrillators nearest to you. It reduces the time to gain access to defibrillation by using the built-in Google Maps function.